DAY-TO-DAY APPROACH FOR PATH CHOICE MODELS IN THE TRANSIT SYSTEM: ANALYTICAL EVALUATIONS AND SIMULATION RESULTS

Over the last few years, the introduction of models of dynamic process in the analysis of the assignment to the transit system has become more important for two main reasons: (1) in analyzing and planning transport systems, dynamic models allow better evaluation of link flows and network performance, such as times and service levels, thanks to the explicit simulation of the evolution of the system in time; (2) in using ITS, ATIS, and/or APTS dynamic models are the only ones that enable user decisions to be evaluated with regard to the evolution of the service in real time, and thus give the user information about predicted flows. Today, the high frequency of urban systems demand a greater attention to the phenomenon of congestion determining the movement of transit vehicles in promiscuous lines, with considerable irregularities of the service and a lower capability to meet the requirements of the demand concerned with the same service and that of the community, which suffers the negative effects of a wrong transport policy. In urban transit systems, besides inter-period (day-to-day) dynamics there are also dynamics within the same day, that is why it must be hypothesized that the evolutionary process arises from the overlapping of two components: the day-to-day and within-day process. The dynamic approach to transit system simulation considers system evolution both during a single-day period (within-day variation) and in successive periods (day-to-day) variation.